1. Field of the Invention
The present invention relates generally to systems and devices for determining geographic information, and specifically to distributed systems and devices for interpreting spatial and geographic data and presenting said data to a user.
2. History of the Related Art
Maps still provide the main means for understanding spatial environments, as well as for performing tasks such as wayfinding, trip-planning, and location-tracking. Static traditional maps have several disadvantages. First, maps necessarily have a fixed orientation. That is, the map always faces in one direction (typically north). The map users, however, may be facing any direction at any given moment. Hence, in order to understand the map users need to perform some kind of rotation, either of themselves or of the map to align their frame of reference with the map's frame of reference. This process puts an immense cognitive load on the users, because it is not always intuitive and may present considerable difficulties, especially in cases of complex, uniform or unfamiliar spatial environments.
Maps are also hindered by the fact that they have a fixed scale that cannot be changed to a different granularity level. This limitation is one of the most restrictive aspects of paper maps. The scale determines the level of zooming into a spatial environment, as well as the level of detail and the type of information that is displayed on a map. Users, however, need to constantly change between different scales, depending on whether they want a detailed view of their immediate surrounding environment or a more extensive and abstract view in order to plan a trip or find a destination. Current solutions to the problem include tourist guides that comprise maps of a specific area at many different scales. Tourist guides, however, are bulky books, difficult to carry around, and search time is considerable as they typically consist of hundreds of pages.
Maps also fail to accommodate rapid changes in our natural and urban environments. On a map, all spatial environments and the objects that they encompass, whether artificial or natural, are displayed statically although they are actually dynamic and change over time. Artificial spatial objects, such as buildings, may get created, destroyed, or extended, while others, such as land parcels, may merge, shrink, or change character (e.g., when a rural area is developed). The same holds true for natural features, for instance, a river may expand or shrink because of a flood. The static 2-dimensional map is restricted to representing a snapshot in time and the information on it may soon become obsolete, or worse, misleading.
Maps are also limited in their ability to display thematic information. There are many different types of maps such as morphological, political, technical, tourist-oriented, and contour maps. The thematic content of a static map must be defined at the time of printing and is usually restricted to one area of interest. Even then, the information displayed is minimal. For example, a tourist map will indicate that a building is a church or a restaurant, but it is highly unlikely that more information will be available, such as the construction date of the church or the menu of the restaurant and the type of cuisine it offers.
Attempts at electronic maps or geographic information systems have also proven unworkable for practical reasons. One deficiency found in current geographic information systems is that the systems are not egocentric, i.e. they cannot discriminate between data based upon the user's point of view and intentions. The state of the art lacks an integrated geographic information system that can provide information to a user in a manner that is easily accessible, intuitively understood, and based upon the user's perspective.